Efficacy and Safety of Low-Dose Amiodarone Therapy for Tachyarrhythmia in Congenital Heart Disease.

Amiodarone (AMD) is a class III anti-arrhythmic drug that is highly effective for tachyarrhythmia treatment. AMD is widely used in adults with congenital heart disease (CHD); however, higher doses of AMD (> 200 mg/day) can cause various non-cardiac side effects. The purpose of this study was to assess the efficacy, safety, and adverse events of low-dose AMD (≤ 200 mg/day) for tachyarrhythmia in patients with CHD. We retrospectively studied 80 patients with CHD and tachyarrhythmia who received oral low-dose AMD (≤ 200 mg/day) from January 2004 to March 2016. Low-dose AMD therapy was used to treat supraventricular tachycardia (SVT) in 51 patients and ventricular tachycardia (VT) in 29 patients. After a mean follow-up of 2.9 years for SVT and 3.2 years for VT, 36% and 65% of the patients with SVT and VT, respectively, were free from a first tachyarrhythmia recurrence for 3 years. The incidence of AMD-induced side effects was 23%, and all these cases consisted of thyroid dysfunction. Low-dose AMD was effective for the treatment of tachyarrhythmia in patients with CHD and had a relatively low incidence of side effects. These findings suggest that low-dose AMD is useful and effective for decreasing the frequency of tachyarrhythmia in patients with CHD and has a low incidence of side effects.